1. Field of the Invention
The present invention relates generally to a means for reducing the height of a chair which utilizes a gas spring fitted into the chair control for adjustability of the chair height. More particularly, the invention relates to a chair control gas spring retainer which is specifically designed to support the chair for reduced chair height as distinguished from current chair constructions.
2. Description of the Related Art
Chairs of a type suitable for use in office environments, for example, are frequently designed with manual adjustment means that permit adjustment of various chair functions. Such adjustments are typically performed by a chair control mechanism positioned beneath the chair seat and supported on a base and pedestal assembly. The adjustable functions may include, for example, chair seat and back tilt and chair height adjustment. An example of such a chair control is disclosed in U.S. Pat. No. 5,427,434 issued to Hybarger.
It is now generally accepted practice to accomplish the chair height adjustment function using a gas spring. The typical gas spring is a tubular mechanism having an internal piston and a release button on its top that can be activated by a simple lever to extend or retract a piston rod in cooperation with the weight of a user seated in the chair. The gas spring often connects directly to the chair control beneath the seat and forms part of a pedestal supported on a swivel base. Depending on the range of desired height adjustment there are generally two types of common gas spring constructions available, that is, a single stage construction and a double stage construction. The double stage construction, while it permits a wider range of height adjustment is, by virtue of its component parts, more expensive to use than a single stage spring construction. Further, with the use of certain multi-function chair controls, it has heretofore been required to use a double stage gas spring construction, according to standard chair control design, to achieve a desired range of seat height adjustability which typically ranges from between 16 inches to 20-1/2 inches. This is so because of the large thickness dimensions of some preferred chair control mechanisms. In this connection, one form of desired chair control mechanism comprises a first lower main housing having a generally upwardly open U-shaped configuration connected by a pivot member to a second downwardly open upper U-shaped housing. The two housings have a substantial thickness dimension to accommodate a tilt mechanism with torsion spring biasing means, for example, as well as tilt limiting and lock out means. In the typical construction of such a control mechanism, the lower housing is fitted with a collar that receives and supports the control on an upper tapered end of the gas spring. By such an arrangement, a single stage gas spring construction of a type that is generally commercially available is too long to achieve the desired range of height adjustability as heretofore mentioned. Again, the standard commercially available gas spring cannot be used with certain thicker dimensioned chair controls in a single stage arrangement of heretofore known construction because of its extended and unextended length characteristics. Thus, in such applications a more expensive double stage gas spring construction must be used. Moreover, even using a double stage gas spring construction it is desirable to provide a chair control construction that retains the spring so as to permit a greater reduction of chair height over chair designs currently available.
Accordingly, it is desirable to provide a new construction of chair control that has such desirable features as adjustable tension seat and back tilt and gas spring chair height adjustment while at the same time provides for reduced chair height as distinguished from known chairs of commercially available types. It is further desirable to provide such a control which is readily manufacturable by known techniques. Still further, it is desirable to provide such a control which is cost-effective to manufacture.